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Author Topic: New User - Stage speed question - Move fault?  (Read 3242 times)

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New User - Stage speed question - Move fault?
« on: May 24, 2010, 11:02:53 AM »
Hello,

I've just recently purchased a 2nd hand Taig 3 axis mill with a MicroMill DSLS 3000 controller.  It has a 1Ghz PC and it's running an older version of Mach3 software circa 2005/2006.

It appears to run well.  I can jog the full stage travel with no problem.  The stages do not bind when I move them by hand.

The problem is that when I run a g-code toolpath, it often will fault and I will have to Reset the system to continue.  It does this on arc  moves or very short back and forth linear motion mostly.   If I slow the feed rate down to say 50% the complete program will run withouth faulting.

I assume the fault is being caused by the motors losing steps or not being able to keep up w/ what the computer is telling it.  Is there a diagnostics log in Mach 3 that I can view to verify this?

The motor settings are max velocity approx 66 ipm and acceleration set to approx 250ms to reach that velocity.  Are there values correct?  Are there any tuning routines that can be run to determine optimal values for this? 

I understand the computer that came with the system is old however Mach 3 is the only thing running on it and the CPU loading when running a toolpath is only about 5-10% so there is no resource problem with the computer.  I know there are new versions of Mach 3.  Those require a newer computer system than what came with the tool.  I'd prefer to get this system running reliably rather than spend significant $$ upgrading hardware.  Is this viable?

I read some posts about a Smooth Stepper USB device.  What is required to convert the system to use this?  What would be the benefit/drawbacks. 

Thanks in advance for any suggestions.

- Dave

Offline Hood

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Re: New User - Stage speed question - Move fault?
« Reply #1 on: May 24, 2010, 02:11:11 PM »
Not sure what you are meaning by " acceleration set to approx 250ms to reach that velocity" if it is set to 250 in/s/s then I think that may be rather fast even for a light machine. Try setting the accel quite a bit lower.
Hood
Re: New User - Stage speed question - Move fault?
« Reply #2 on: May 24, 2010, 02:29:25 PM »
I'm sorry I wasn't clear.  I was basing the 250ms timing by the acceleration/velocity profile graph that is displayed in Mach 3.  In that graph, the acceleration ramp takes 250ms to reach the velocity of 66 IPM.  I'll try to figure out what acceleration that converts to.

My gut feel is that the acceleration is not the problem since it has no problem jogging or running longer X or Y stage motion.  The failure only occurs running curves or very short back and forth X or Y motion.

Offline budman68

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Re: New User - Stage speed question - Move fault?
« Reply #3 on: May 24, 2010, 03:35:37 PM »
Hi Dave,

I'm including the original XML file from my Dsls3000 for you. Depending on how "tight or loose" you can get away with running your machine, the numbers will need to be adjusted.

My personal current settings are at:

X= 60 vel.     4.4 acc.
Y=42.5 vel.   4.3 acc.
Z= 56.8 vel   5.67 acc.

Hope that helps-
Dave

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Re: New User - Stage speed question - Move fault?
« Reply #4 on: May 24, 2010, 04:09:55 PM »
Thank you.  I'll see how that compares w/ mine. 

Just for my information, when you set a maximum feed rate in Mach 3 at say 60 in the motor configuration page, that sets the upper limit on what a G-code Feedrate command can be, right?  I noticed that my toolpath ran correctly when I had errantly told BobCad that I was milling soft steel.  The feedrate was set to approximately 4.  When I corrected my error and indicated that I was milling aluminum, the feedrate was set to approximately 20.  The same toolpath that ran correctly slowly caused the fault running at the faster rates.

Offline budman68

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Re: New User - Stage speed question - Move fault?
« Reply #5 on: May 24, 2010, 04:15:38 PM »
Hi Dave,

The velocity will be what your "rapids" (or rapid movement to get from one operation to the next) will run at, not your cutter speed.

Dave
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Re: New User - Stage speed question - Move fault?
« Reply #6 on: May 28, 2010, 08:37:14 PM »
A couple more questoins:

Does Mach 3 maintain an error log that I can review to find out which axis is causing the Reset fault? I am running an older version on a 1 Ghz machine. 

Also, how does the maximum stage speed set in Mach 3 relate to the "F" feedrate commands in the G-code? 

Does backing off the feedrate from 100% to say 50% do exactly the same as halving the "F" rate?  Is there any difference?

Thanks.

Offline Hood

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Re: New User - Stage speed question - Move fault?
« Reply #7 on: May 28, 2010, 09:34:39 PM »
Lets go back to the beginning, you say "The problem is that when I run a g-code toolpath, it often will fault and I will have to Reset the system to continue"
When Mach faults is there an error message in the ticker line?
Sounds like you may have noise or vibration issues which are triggering your limit switches, try increasing the Debounce Interval to 2000, its on General Config page at the top right.

Hood